patch 8.2.1813: Vim9: can assign wrong type to script dict

Problem:    Vim9: can assign wrong type to script dict. (Christian J.  Robinson)
Solution:   Check the type if known.

src/eval.c

@@ -887,6 +887,17 @@ get_lval(
 	    return NULL;
 	}
 
+	if (in_vim9script() && lp->ll_valtype == NULL
+		&& lp->ll_tv == &v->di_tv
+		&& ht != NULL && ht == get_script_local_ht())
+	{
+	    svar_T  *sv = find_typval_in_script(lp->ll_tv);
+
+	    // Vim9 script local variable: get the type
+	    if (sv != NULL)
+		lp->ll_valtype = sv->sv_type;
+	}
+
 	len = -1;
 	if (*p == '.')
 	{
@@ -1037,6 +1048,10 @@ get_lval(
 		}
 	    }
 
+	    if (lp->ll_valtype != NULL)
+		// use the type of the member
+		lp->ll_valtype = lp->ll_valtype->tt_member;
+
 	    if (lp->ll_di == NULL)
 	    {
 		// Can't add "v:" or "a:" variable.
@@ -1148,6 +1163,10 @@ get_lval(
 		return NULL;
 	    }
 
+	    if (lp->ll_valtype != NULL)
+		// use the type of the member
+		lp->ll_valtype = lp->ll_valtype->tt_member;
+
 	    /*
 	     * May need to find the item or absolute index for the second
 	     * index of a range.
@@ -1383,6 +1402,11 @@ set_var_lval(
 	    emsg(_("E996: Cannot lock a list or dict"));
 	    return;
 	}
+
+	if (lp->ll_valtype != NULL
+			&& check_typval_type(lp->ll_valtype, rettv, 0) == FAIL)
+	    return;
+
 	if (lp->ll_newkey != NULL)
 	{
 	    if (op != NULL && *op != '=')

src/proto/evalvars.pro

@@ -58,6 +58,7 @@ int eval_variable(char_u *name, int len, typval_T *rettv, dictitem_T **dip, int
 void check_vars(char_u *name, int len);
 dictitem_T *find_var(char_u *name, hashtab_T **htp, int no_autoload);
 dictitem_T *find_var_in_ht(hashtab_T *ht, int htname, char_u *varname, int no_autoload);
+hashtab_T *get_script_local_ht(void);
 void *lookup_scriptvar(char_u *name, size_t len, cctx_T *dummy);
 hashtab_T *find_var_ht(char_u *name, char_u **varname);
 char_u *get_var_value(char_u *name);

src/proto/vim9script.pro

@@ -8,5 +8,6 @@ void ex_import(exarg_T *eap);
 int find_exported(int sid, char_u *name, ufunc_T **ufunc, type_T **type);
 char_u *handle_import(char_u *arg_start, garray_T *gap, int import_sid, evalarg_T *evalarg, void *cctx);
 char_u *vim9_declare_scriptvar(exarg_T *eap, char_u *arg);
+svar_T *find_typval_in_script(typval_T *dest);
 int check_script_var_type(typval_T *dest, typval_T *value, char_u *name);
 /* vim: set ft=c : */

src/structs.h

@@ -4055,6 +4055,7 @@ typedef struct lval_S
     dict_T	*ll_dict;	// The Dictionary or NULL
     dictitem_T	*ll_di;		// The dictitem or NULL
     char_u	*ll_newkey;	// New key for Dict in alloc. mem or NULL.
+    type_T	*ll_valtype;	// type expected for the value or NULL
     blob_T	*ll_blob;	// The Blob or NULL
 } lval_T;
 

src/testdir/test_vim9_script.vim

@@ -145,6 +145,15 @@ def Test_wrong_type()
   CheckDefFailure(['var Ref: string', 'var res = Ref()'], 'E1085:')
 enddef
 
+def Test_script_wrong_type()
+  var lines =<< trim END
+      vim9script
+      var s:dict: dict<string>
+      s:dict['a'] = ['x']
+  END
+  CheckScriptFailure(lines, 'E1012: Type mismatch; expected string but got list<string>', 3)
+enddef
+
 def Test_const()
   CheckDefFailure(['final name = 234', 'name = 99'], 'E1018:')
   CheckDefFailure(['final one = 234', 'var one = 99'], 'E1017:')

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1813,
 /**/
     1812,
 /**/

src/vim9script.c

@@ -565,18 +565,18 @@ vim9_declare_scriptvar(exarg_T *eap, char_u *arg)
 }
 
 /*
- * Check if the type of script variable "dest" allows assigning "value".
+ * Find the script-local variable that links to "dest".
- * If needed convert "value" to a bool.
+ * Returns NULL if not found.
  */
-    int
+    svar_T *
-check_script_var_type(typval_T *dest, typval_T *value, char_u *name)
+find_typval_in_script(typval_T *dest)
 {
     scriptitem_T    *si = SCRIPT_ITEM(current_sctx.sc_sid);
     int		    idx;
 
     if (si->sn_version != SCRIPT_VERSION_VIM9)
 	// legacy script doesn't store variable types
-	return OK;
+	return NULL;
 
     // Find the svar_T in sn_var_vals.
     for (idx = 0; idx < si->sn_var_vals.ga_len; ++idx)
@@ -584,9 +584,24 @@ check_script_var_type(typval_T *dest, typval_T *value, char_u *name)
 	svar_T    *sv = ((svar_T *)si->sn_var_vals.ga_data) + idx;
 
 	if (sv->sv_tv == dest)
+	    return sv;
+    }
+    iemsg("check_script_var_type(): not found");
+    return NULL;
+}
+
+/*
+ * Check if the type of script variable "dest" allows assigning "value".
+ * If needed convert "value" to a bool.
+ */
+    int
+check_script_var_type(typval_T *dest, typval_T *value, char_u *name)
 {
+    svar_T  *sv = find_typval_in_script(dest);
     int	    ret;
 
+    if (sv != NULL)
+    {
 	if (sv->sv_const)
 	{
 	    semsg(_(e_readonlyvar), name);
@@ -604,8 +619,7 @@ check_script_var_type(typval_T *dest, typval_T *value, char_u *name)
 	}
 	return ret;
     }
-    }
+
-    iemsg("check_script_var_type(): not found");
     return OK; // not really
 }